Human immunosuppressive virus (HIV), which is also called human T-lymphotropic virus type III (HTLV-III), lymphadenopathy-associated virus (LAV), or AIDS-associated retrovirus (ARV) is cytopathic for helper/inducer T-cells and is the etiologic agent of acquired immunodeficiency syndrome (AIDS) and related diseases.
Various alkyl derivatives of pyrimidines and purines and analogues thereof have been found to exhibit a wide range of biological activity, cf. Keller et al., Biochem. Pharmacol. 30, 3071 ( 1981); European Patent No. 55,239; European Patent No. 146,516; Hua et al., J. Med. Chem. 30, 198 (1987); Phadtare et al., J. Med. Chem. 30, 437 (1987). Additionally, 2',3'-dideoxynucleosides and related compounds have been found effective against HIV, cf. Mitsuya et al., Proc. Nat. Acad. Sci. USA 83, 1911 (1986); Mitsuya et al. Proc. Nat. Acad. Sci. USA, 82, 7096 (1985); Herdewijn et al., J. Med. Chem. 30, 1270 (1987); Mitsuya et al. Nature 325, 773 (1987); Mitsuya et al. in "AIDS, Modern Concepts and Therapeutic Challenges" (S. Broder, Ed.), 1987, Marcel Dekker, New York, p.303.